Gimp-feed mechanism for buttonholestitching machines



H. PUDELKO Sept. 27, 1966 GIMP-FEED MECHANISM FOR BUTTONHOLESTITCHING MACHINES Filed June 28, 1965 4 Sheets-Sheet 1 H. PUDELKO INVENTOR.

H. PUDELKO Sept. 27, 1966 GIMF-FEED MECHANISM FOR BUTTONHOLE-STITCHING MACHINES Filed June 28, 1965 4 Sheets-Sheet 2 INVENTOR.

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United States Patent 3,274,962 GIMP-FEED MECHANEM FOR BUTTQNHOLE- SllllllfiHHNG MACHINES Hermann Pudeliro, lliielefeld, Germany, assignor to Diirkoppwerhe Alrtiengesellschaft, lliielefeld, Germany, a corporation of Germany Filed. one 28, 1965, Ser. No. 467,438 Claims priority, application Germany, Aug. 26, 1964, D 45,278 12 Claims. (Cl. 1l265) The present application is a continuation-in-part of my copending application Ser. No. 431,319 filed February 9, 1965.

The instant invention relates to gimp-feed mechanisms for automatic buttonhole-stitching machines and, more particularly, to improvements in the gimp-feeding system of machines of the general type described and claimed in the above-identified copending application.

In the aforementioned copending application there is described and claimed a buttonhole-stitching device in which the fabric to be provided with the buttonhole is clamped upon a table and shifted therewith into the buttonhole-stitching position in which a buttonhole is formed by a vertically reciprocating needle. At the conclusion of this operation, the table is returned to its initial position in which the thread may be severed from the buttonhole without interference by the buttonhole-stitching methods. In this application, moreover, and in my application Ser. No. 328,988 filed December 9, 1963, I describe the feeding of a gimp or stiffening (stay) cord to the buttonholestitching location for incorporation in the buttonhole seam to form a bead surrounding the latter when the buttonhole is cut through.

In such apparatus and in other automatic buttonholestitching systems, difliculties are frequently encountered in the positioning and supply of the gimp or stiffening cord to the stitching location at the commencement of the operation. Thus it is desirable in most cases to begin the buttonhole-stitching operation with a bead at one end of the buttonhole from which the relative displacement of the fabric and of the buttonhole-stitching mechanism (e.g. needle, etc.) permits an oval continuation until the buttonhole stitch is completed and terminates at this bead. For the purposes of the present invention, the term stitchforming means will be used to designate arrangements, such as that described in application Ser. No. 328,968 and in application Ser. No. 431,319, capable of forming the oval buttonhole by, for example, swinging movement of a turntable carrying the needle and the means cooperating therewith for making the stitch; thus the sewing needle and the cooperating mechanisms below the fabric are disposed about an upright axis and are swingable about this axis through an angle of substantially 180 to form the eye portion of the buttonhole. The longitudinal edges thereof are stitched upon a substantially linear reciprocating movement of the fabric-carrying table which is displaceable relatively to the stitch-forming means. The initial bead described above is produced by a similar linear movement, thereby anchoring the buttonhole-stitching thread and the gimp to the fabric before the edges of the buttonhole which are to flank the opening are formed. Upon conclusion of the stitching operation, the final bead is formed over or along the initial bead to anchor the finishing end of the thread and gimp or staycord. The stitching in advance of buttonhole formation will be termed hereinafter the initial bead while the final stitching preparatorily to severing of the thread will be designated the final bead. It may now be stated that many of the difiicul-ties involved in the use of a gimp thread or staycord arise because of the nature of the systems sup- 3,274,962 Patented Sept. 27, 1966 plying the gimp thread to the stitching location for the initial bead and during the course of the buttonhole-stitching operation. Thus automatic buttonhole-stitching apparatus have been provided with a feed mechanism which removes from the gimp supply (eg a bobbin or spool of gimp cord), a length of gimp equal substantially to that required for the forthcoming stitching operation, and holds this supply in readiness at the stitching location. The gimp is fed without tensioning to the stitching location for the formation of the initial bead and then is stitched around the eye of the buttonhole. Mechanism can be provided in the conventional systems for insuring that the prepared length of gimp lies properly for the subsequent stitch-ing operation. This mechanism is actuated upon initiation of the machine cycle and is rendered ineffective by many disorders commonly occurring in the gimp-feed arrangement. Thus it is not uncommon for the apparatus to commence operation under circumstances in which a length of gimp has not been supplied; the result is a defective buttonhole. Moreover, when the gimp thread loops at the supply spool, it frequently cannot be fed readily to the stitching location during the next: cycle. The problem thus can be defined as one which requires that the gimp be supplied positively and without interference to the stitching location for commencement of each buttonhole-stitching operation, that proper tension is maintained upon the gimp for the required period without interference with the laying-in operation, and that the gimp thread be held in readiness for the next cycle and not dislodged.

It is the principal object of the present invention to provide an improved system for the feeding of the gimp of staycord to the stitching location of an automatic buttonhole-stitching machine and, more particularly, a buttonhole-stitching machine of the general type described in copending application Ser. No. 431,319, wherein the disadvantages of conventional gimp-feed systems are obvirated.

Another object of this invention is to provide an improved gimp-feed system for positioning a loose length of gimp thread at the buttonhole-stitching location independent of the operating cycle of the stitching mechanism so that the buttonhole-stitching operation itself cannot influence the preparation of the length of gimp.

These objects and others which will become apparent hereinafter are attained in accordance with. the present invention by providing, in an automatic buttonhole-stitching machine having a stitch-forming means, a fabriccarrying table cooperating with this means for producing a buttonhole, and drive mechanism for operating the turntable and the stitch-forming means with the requisite correlation and actuating element for this mechanism having a limited play or initial movement prior to triggering the mechanism, gimp-feed means forming a path for a gimp-thread extending from a supply (e.g. a spool) to the stitch-forming location and clamp means between the supply means and this location for engaging the gimp; the gimp, according to this invention, is engageable by the actuating element at a location behind this clamping means (i.e. between the clamping means and the supply means) for drawing a length of gimp from the supply means when the actuating element is displaced in advance of operation of the drive mechanism for commencing the buttonhole-stitching operation. Only after this actuating element has prepared a loose length of gimp suflicient to complete the forthcoming buttonhole does the actuating member place in operation the stitchforming means.

According to a more specific feature of the present invention, the clamping means retains the gimp during its stitching into the initial bead and cooperates with the turntable (or the means for displacing same) so that only upon the development of the operating cycle does the clamping means open to release the gimp after it has been stitched and thus fixed in place during the initial bead. The clamping means can comprise a rockable clamping plate mounted upon the turntable and engageable with the gimp to clamp the latter against the turntable, control means being provided on the table and the support means of the machine for operating this plate. Advantageously, the control means can include a camoperable actuating member carried by the turntable and engageable with the plate for displacing the same, latch means cooperating with this lever for releasably locking the latter in a position in which the clamp is engaged, and cam means on the turntable or support for camming the lever into its latched position to clamp the gimp and for tripping the latch means to release the lever when the gimp is to be released.

The clamping means may thus be provided with a pair of cams for the opening and closing of the latch means and disposed at spaced-apart locations in the direction of travel of the table; it is another specific feature of this invention to provide means for relatively adjusting these cams thereby accommodating this system to buttonholes of substantially any length. Since the latch means and the clamping plate normally engage the thread except during part of the buttonhole-stitching operation, 1 provide manually operable means for releasing the latch means and displacing the plate to release the gimp in order to permit the operator to feed a new gimp thread into position along the gimp-feed path.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a side-elevational view of an automatic buttonhole-stitching machine provided with thread-severing means and an actuating system as described in my copending application Ser. No. 431,319, but having the im proved gimp-feed means of the instant invention;

FIG. 2 is a partial plan view, with parts removed, of the machine of FIG. 1;

FIG. 3 is a plan view of the stitch-forming and gimpfeed means thereof in the region of the stitching location;

FIG. 4 is a detail view, drawn to an enlarged scale and partially broken away, of the gimp-clamping means of the instant invention; and

FIG. 5 is a cross-sectional view taken along the line VV of the FIG. 4, drawn to a still larger scale.

General description of the buttonhole-stitching apparatus As can be seen from FIGS. 1-3, the buttonhole-stitching machine of the present invention is essentially identical with that illustrated and described in my copending application Ser. No. 431,319 and entitled Buttonhole- Stitching Machine and Thread-severing Therefor. The apparatus comprises a base or housing, generally designated 1, upon which a fixed but removable upper portion or arm-forming member of the support means is mounted. In the usual manner, this arm-forming upper portion contains the control and severing mechanism for the buttonhole-stitching and thread-severing units. The housing 1 is, in turn, mounted upon the usual foundation plate (not illustrated), and carries a longitudinally shiftable fabriccarrying table 3 at this upper portion 2 of the support means. As described in the last-mentioned copending application, a pair of fabric-clamping arms 4' and 4", pivotably secured to the table, form a fabric-clamping means generally designated 4, the shoes 4a and 4a" of these arms being disposed above the fabric and having roughened undersurfaces engageable with the fabric from above to hold it during the buttonhole-shifting operation and during movement of the fabric-carrying table 3. From FIG. 3, it will be seen that the shoes 41:, 4a" define between them a gap in which the buttonhole K (shown in dot-dash lines) is to be formed. The stitch-forming means 5 can include a generally vertically reciprocable needle 5a, mounted on the arm 2a of the upper support portion and cooperating with a turntable 5b of the type described in copending application Ser. No. 328,938 for producing the buttonhole seams. While this structure is amply described in the latter application, it may be mentioned that the linear or essentially linear edges or portions of a buttonhole seam are formed by displacing the table 3 substantially linearly whereas the eye or oval extremities of the buttonhole are formed by rotating the turntable 5b and the needle assembly 5a cooperating therewith through an angle of up to 180 at each end of the buttonhole. The composite movements of turntable 5b and table 3 permit buttonholes of any desirable configuration to be formed with ease. The stitch-forming means 5 is swingable about the vertical axis XX (FIG. 1) and includes a stitching plate 6 having a needle passage 7 aligned with the needle and a bore 8 through which the gimp G is supplied directly to the stitching location 7. The detailed construction of the stitch plate and the gimpfeed means at the stitch-forming location is fully described in application Ser. No. 328,938. The upperand underthreads are also supplied to the stitching location in the manner described in this copending application although these threads have not been shown in FIGS. 1 and 3 to avoid obscuring the structural elements necessary to a clear picture of the present invention. It may, however, be noted that a thread brake 11 is provided for adjustably impeding the withdrawal of the upper thread from its supply spool to tension this thread and insure the formation of a tight stitch during the buttonhole-stitching operation and especially during the formation of the initial seam; this guarantees the firm initial attachment of the gimp to the fabric. The thread brake 11 can be any conventional braking device commonly in use with sewing machines and the like and, for example, can be constituted by a frictional disk in contact with the periphery of the supply spool.

As described in copending application Ser. No. 431,319, the apparatus is also provided with a thread-severing means (generally designated 16) which is actuated in the cadence of reciprocation of table 3 to sever the gimp and sewing threads as close to the buttonhole as possible. While the thread-severing means is fully described in this latter application, it may be briefly mentioned that the actuating means for the thread-severing device can comprise a slide formed with a non-swingable blade member 118 and a swingable blade member 119; the blades thus cooperate to form a scissor which, in its rest position, is held in an open condition (FIG. 2). A bladeactuating mechanism is also provided and includes an angularly oscillatable shaft 123, journaled in the housing 1, and normally held by the torsion spring 169 in a rest position corresponding to the open position of the blade members. An actuating lever for the shaft 123 is provided at 126 while a spring 128 couples this lever with a pedal or other operating element which may be tripped by the operator to initiate the thread-severing operation. The motion of shaft 123 is transmitted, via a pivotal arm 133 to a pair of slides 135, 138 which control a swingable lever 147; the latter, in turn, operates a pair of arms 151, 153 by means of which motion is transmitted to the blades 18 and 19 via the pins 154- and 152. The thread-severing means is also provided with a lockout mechanism, generally designated L and fully described in application Ser. No. 431,319, cooperating with the actuating means of the apparatus for preventing the functioning of the blade means during reciprocation of the table but permitting such operation upon return of the table to a position in which thread-severing is to be effected. This mechanism, moreover, cooperates with an actuating element of the drive means (e.g. lever 24) of the apparatus to prevent the operation thereof and the displacement of the table during the thread-severing step.

While the operation of the gimp-feeding system will be described in greater detail hereinafter, it may be noted that both the fabric-carrying plate 3 and the clamping device 4 are actuated by the programming and drive means of the apparatus after tripping of the drive means by an actuating element. The latter thus sets into operation a predetermined sequence of steps which include the shifting of the table or plate 3 from its starting position into the stitch-forming position. When the table is in the latter position, the stitch-forming turntable is operated, also by the drive and control means, to impart to the buttonhole the configuration of the eye; upon termination of the eye-forming step, the turntable is brought again toward its initial position to permit the thread-severing operation to be carried out. From this position, the table is again moved forwardly at the commencement of operation of the apparatus. The blades 118 and 113 are positioned (FIG. 2) to sever both the gimp G and the underthread U directly at the buttonhole seam at the conclusion of the stitch-forming operation thereby eliminating any need for additional operations to remove excessively long tails.

The driving and programming means of the apparatus can include any conventional cam arrangement but preferably comprises a clutch mechanism 13 of the type described in application Ser. No. 431,319. The clutch means 13 (FIGS. 1 and 2) is disposed between a driveshaft 14 carrying a V-belt pulley 15 over which the belt 16 passes. The belt 16 is driven by the main power means of the plant, e.g. a shaft extending along a bank of similar machines and provided with respective pulleys each driving the belt of a corresponding machine. The pulley 15 thus operates continuously and acts as a flywheel which rotates the driven shaft 114 upon actuating of the clutch 13. Shaft 114 drives via respective transmission gears, a pair of cams 1% and 114 which control the movement of the table 3 and the turntable of the stitchforming means. The clutch means 13 is provided with an actuating element 17, 22 extending from a forward location on the machine, at which it is accessible to the operator, to a rearward location proximal to the vertical axial plane of the shaft 14. This actuating element is pivotally mounted in a trunnion 20 upon the fabriccarrying table 3 and is provided with an arm 22 which extends generally parallel thereto, while its longitudinal extension or shank 22 runs rearwardly along the plate to the region of the clutch means 13. An arm 23 of the actuating lever 17 serves as a handle manipulable by the operator for displacing the actuating lever and thereby tripping the clutch 13 to commence operation of the machine. For this purpose, the lever 17 also is provided with an arm 24 which is connected with the clutch and permits a substantial clockwise movement (FIG. 1) of the lever 17 in its trunnion 20 before the clutch is triggered.

Gimp-feed system The gimp cord G passes from a supply spool 19, mounted upon a pedestal 19' of a stand 19" rearwardly of the machine via a central unwinding guide 1% and a pair of additional guides 19b and 19c through a pair of eyelets 28 and 29 of the gimp-preparing device 18 which serves to form a loop of the gimp cord before feeding it through the gimp-clamping means 25; the latter is disposed forwardly along the feed path of the gimp thread but rearwardly of stitch plate 6 and the bore 8. The gimp-clamping means 25 will be described in greater detail hereinafter.

Gimp-preparation means The arm 22 is so disposed that it lies between the eyelets 28 and 29 while the gimp thread passes over it so that, upon initial movement of lever 17 and the swinging of arm 22 and its shank 22' in the clockwise direction, the gimp G is lifted between these eyelets and withdrawn from the spool 19 via eyelet 28. When the arm 22 and its shank 22 are subsequently released, a loop or supply of the gimp cord in an untensioned state, is provided between the supply spool 19 and the gimp-clamping means 25. The motion of the arm 22, 22' which serves to prepare the loop of gimp cord behind the clamping means is the lost motion of the actuating element prior to the tripping of the clutch means 13 thereby. The loop of gimp thus lies on the table 3 and permits the free end of the gimp at the stitching location (upon movement of the table into stitch-forming position) to be stitched into the initial bead and the subsequent buttonhole in a tensionless state.

The eyelets through which the gimp passes are mounted upon or integral with an L-shaped member 30 whose flange 30 is bolted at 30 to the upstanding portion 2 of the support while its horizontal portion 38 lies parallel to the table 30. The shank 22' of arm 22 lies between the eyes 28 and 29 upon this horizontal portion 30a of member 30 which extends generally transversely to the path of the gimp and the shank of the bar. The gimp G, however, passes over the shank 22 and is in contact therewith at 27 so that an elevation of shank 22', upon clockwise movement (FIG. 1) of lever 17 will draw the gimp between the eyes 28 and 29 into an upstanding loop, Upon the downward movement of the shank 22 (corresponding to the counterclockwise swing of actuating lever 17), a loop is formed at 26 in readiness for the buttonhole-stitching operation and the initial movement of the table 3 which commences only subsequently to the formation of this loop.

The gimp-feed means also comprises a clamping means 25 whose purpose is to ensure that, during operation of the gimp-preparation element (i.e. arm 22) through the gimp is drawn from the supply spool 19 and not away from the stitching position of the table. The clamping means thus locks the gimp G to the table and does not, during preparation of the loop of gimp cord, permit withdrawal of the free extremity of this cord through the clamp. The clamping means has, however, another function which will become more readily apparent from the following description of its operation, namely the withdrawal or retraction of the free end of the gimp, to a limited extent upon the severing of the gimp from the buttonhole. It will be readily apparent that, if the gimp is excessively withdrawn, it will not be stitched firmly in place during the initial bead stitching operation; if the withdrawal is not suflicient, a portion of gimp will extend from the buttonhole seam thereby necessitating a manual removal of the projecting portion.

Gimp-clamping means The gimp clamp 25 comprises a rockable clamping plate 33 (FIGS. 2, 4 and 5) and a clamp-control mechanism generally designated 34 (FIGS. 1 and 4) which includes latch means for locking the clamp in engagement with the gimp and for rocking it out of engagement with the latter.

The clamping plate 33 (FIGS. 2 and 4) is generally rectangular sheet-metal plate bent to an obtuse angle substantially along a median line parallel its longitudinal edges. The plate 33 is integrally formed with projections or arms 35 and 36, the former serving to clamp the gimp G against the upper surface of the fabric-carrying plate 3 (FIG. 5), while the latter arm cooperates with the control mechanism 34 for imparting swinging movement to the plate 33. Plate 33 is formed with a pair of frustoconically countersunk bores 42 (one which is shown in FIG. 5) along the bend line of plate 33 (FIG. 2). These bores receive respective screws 39 which constitute part of the mounting means for rockably aflixing the plate 33 to the table 3. Each of the screws 39 has a f'rustoconical head 38 which holds a respective split ring 41 within the bore 42. Thus the tightening of the screws 39, via the slotted heads 40, can radially expand or spread the rings 41 against the wall of the respective bore 14 and increase the frictional engagement therewith and thus the force required for swinging the plate 33. The rings 41 have ballshaped (i.e. generally spheroidal) outer surfaces 41 in engagement with the frustoconical bores 42, thereby permitting a swivel movement of the clamping plate 33. The countersinks of the rings 41 terminate at cylindrical portions 41" through which the shank of the respective screw 39 passes, the rings 41 hearing at 41" against the upper surface of the fabric-carrying plate 3. By proper selection of the relative dimensions of the frustoconical bores 42 and the ball surfaces of rings 41, the plate 33 can be provided with more or less play with respect to the upper surface of plate 3, thereby permitting the clamp to accommodate gimp cords G of different thickness. As previously indicated, the clamping stress applied to the cord can be adjusted by tightening or loosening the screws.

Arm 36 at the outward end of plate 33 is bent downwardly at an obtuse angle to the plate and is receivable within a slot-shaped mouth 43 of a double arm lever 44. Lever 44 is swingably mounted upon the fabric-carrying table 3 by a pivot 45. When the lever 44 is swung downwardly at its mouth 43 (clockwise in FIG. 4), the projection 36 is engaged in the mouth 43 and entrained downwardly by lever 44 so that the plate 33 tends to swing about its fulcrum 38 and clamp the gimp. The gimp is thus firmly held in place beneath arm 35 of plate 33. When lever 44 is swung about its pivot 45 in the counterclockwise sense, however, the clamp plate 33 is lifted at its arm 35 and the gimp is released. In addition to lever 44, the clamp-control means comprises latching means in the form of a lever 62 for locking lever 44 in its extreme clockwise position, i.e. latching the clamp in engagement with the gimp. To close the gimp clamp 25, the lever 44 is provided with a cam-follower means in the form of a roller journaled upon a pin 52 and engageable with a cam means 46 in the path of this roller when the table 3 is shifted to the left (FIG. 4). The cam means 46 comprises an upright double-arm lever 42 .swingably mounted at 50 to a support bar 48 on the lower housing portion 9 below the table (FIGS. 2 and 3). The upper arm 49" of lever 49 is provided with a camming surface 49' which is engageable with the roller 52 and thus cams the latter upwardly as the table 3 is shifted to the left into engagement with the lever 49 (FIG. 1). The lever 44 is thereby swung in the clockwise sense.

For the opening of the gimp clamp 25, I provide a second cam means 47 adapted to swing the lever 44 indirectly in the counterclockwise sense (FIG. 4). The cam means 47 operates via the latch means 62. The latter is a further double-arm lever whose hooked extremity 64 is engageable with an abutment 44 adjacent the mouth 43 of lever 44. The lever 62 is pivotally mounted at 63 on the fabric-carrying plate 3 and is provided with a roller 61) upon its arm 62 for engagement with the cam 67 of camming means 47. Roller 60 thus constitutes a cam-follower journaled upon a bolt 61. To adjust the cam 67 with respect to the point in which the clamp plate 33 will release the cam, I provide a support arm 48 (FIGS. 2 and 4) whose groove 48" forms a slide for the cam 67 of camming means 47. The shifting of the cam 67 is carried out by means of a threaded spindle 70 which threadedly engages the cam 67 and passes through the groove 48" through a support disk 68' which is held in place by a nut 68. Release of the nut 68 permits separation of the cam 67 to permit the latter to be withdrawn from its guide groove 48". The spindle 70 is provided with a shoulder 70 by which it is retained in cam 48 against axial displacement, while a knurled or milled knob 70" is affixed to the spindle to permit its manual rotation.

The adjustment of the cam means 46, i.e. the positioning of the camming surface 49' of lever 49, is carried out by means of a cylindrical-head screw 53 which is received with clearance in a hole 54 of the support arm 48.

Bolt 53 is threaded into the arm 49" of lever 49 and is locked in place by a counter nut. Moreover, a pin 56 is clamped by a set screw 57 in arm 49' and extends parallel to the bolt 53 through an opening 48 in support arm 48. The pin 56 projects upwardly beyond the support arm 48 so that it is engageable with the underside of arm 62 of the latching lever 62. A compression spring 58 is disposed between the support arm 48 and arm 49" of lever 49, this spring holding the lever 49 in its extreme clockwise position. By adjusting the height of surface 49 via screw 53, it is possible to actuate the lever 44 of the clamp-control means 43 sooner or later. Thus the release of the clamp and its latching can be accurately established with respect to the movement of the table 3.

In order to swing the lever 62 into latching engagement with lever 44, there is provided a spring means 65 which bears upon a pressure pin 66 shiftable in the bore 65 of lever 44. The pin 66 bears against the arm 62' of lever 62 and thus tends to urge this lever in the counterclockwise sense.

Gimp-guide means To guide the gimp G between the location 26 at which the length of gimp is prepared by actuating element 22 and the gimp clamp 25, there is provided a tube 71 (FIG. 2) which terminates at the clamp 25. Tube 71 is affixed by means of a screw 72 to the fabric-carrying table 3. A large-head bolt 73 is provided in the region of the clamp 25 to guide the gimp below the clamping surface of projection 35 of plate 33 and holds the gimp to the fabriccarrying table. The bolt 73 can, however, also be provided with the deflecting roller 74 (FIG. 4) about which the gimp G passes as it is directed toward the opening 8 in the stitch plate. Between the gimp clamp 25 and the stitch plate, a further guide tube 75 (FIGS. 2 and 3) is provided on the fabric-carrying table and is so bent that the gimp G passes directly around a guide roller 76 (FIG. 3) through the bore 8. Roller 76 is fastened on the turntable of the lower portion of the stitch-forming means as described in the aforementioned copending application Ser. No. 328,938.

Operation After a fabric has been layed fiat upon the fabriccarrying table 3 and clamped by the clamping device 4 in the conventional manner and as described in both of my prior applications mentioned above, the actuating lever 17 is displaced in the clockwise sense by pushing its arm 23 downwardly (FIG. 1). During the initial part of the movement of lever 17, prior to actuation of the clutch means 13 of the drive of the machine, the shank 22' lifts between the gimp-guiding eyes 28 and 29. Thus the gimp between these eyes is drawn upwardly into a loop. The length of gimp forming this loop is drawn from the gimpsupply spool 19 through eye 23 since the gimp clamp 25 is in its latched position holding the gimp in place. The gimp clamp 25 latches at the end of the previous buttonhole-stitching operation since the cam-follower roller 51, at the conclusion of the stitching cycle and during the return movement of the fabric-carrying table 3 to its starting position, is held up by the cam 49. Lever 44 is thereby swung in a clockwise sense about its pivot 45 while the pressure pin 66 has swung the latching lever 62 in the counterclockwise sense into engagement with the abutment 44. Thus the gimp G is held in place during the lost-motion or gimp-preparation stroke of the actuating element 17. After this initial movement of the actuating element, clutch 13 is tripped and sets the automatic cycle in operation. When the gimp G, because of an interference in the gimp supply, prevents the loop formation, further actuation of lever 17 is not possible since the shank 22' is retained by the gimp. The automatic cycle thus cannot begin until the difficulty has been corrected.

The lever 17 returns to its rest position by the force of a restoring spring (not shown) or the weight of arm 22 to permit the loop of gimp, whose length is equal substantially to that required for the buttonhole-stitching operation, to gather at 26. In the first phase of the automatic cycle, as described in applicaion Ser. No. 431,319, the forward movement of the fabric-carrying table 3 from its starting position to the so-called stitching position continues without modification of the gimp-feeding arrangement until the roller 60 engages the cam 47 to release the latch 62. During this movement and prior to release of the clamp 25, the clamp 25 retains the gimp and positions it accurately at the stitching location. The relative movement of the gimp clamp and the stitching position during this initial period of operation of the drive means is the amount of the total forward stroke of the turntable necessary to return the gimp to the stitching location and corresponds essentially to the displacement of the table 3 after the conclusion of the previous stitching operation.

This portion of the movement of table 3 prior to commencement of stitching determines the length of the buttonhole. To ensure that the free end of the gimp severed from the previously formed buttonhole by the blade means 113, 119, is accurately positioned at the stitching location, the spindle 70 is rotated to shift the cam 67 such that the clamp does not open until the free end of the gimp is properly disposed at the stitching location. This guarantees that the first stitches of the initial bead B will fasten the free end of the gimp in place. When this has occurred, the lever 62 releases the lever 44 and .plate 33 is swung out of engagement with the gimp by the spring 65. The gimp is then drawn unhindered during the remainder of the buttonhole-stitching operation from the supply loop at 26. At the conclusion of the buttonhole-stitching operation, the table 3 is again shifted to its starting position. This movement bringing the roller 51 into engagement with the camming means 46 which thus swings lever 44 in a clockwise sense to clamp plate 33 against the gimp. Spring 65 swings lever 62 so that its hook 64 latches lever 44 and locks the gimp clamp closed. The severing operation at the blade means 118 and 119 can then be carried out and the fabric removed for the next buttonhole-stitching operation.

Since the feeding of the gimp G below the arm 35 of plate 33 cannot be carried out with the clamp 25 in a latched position, and since the clamp is normally latched in the off position of the machine (FIG. 1), I provide means for manually releasing the clamp to permit insertion of the gimp. For this purpose a handle 59 is provided for the lever 49 (FIGS. 1 and 4) by means of which the lever 49 can be swung against the force of spring 58 (counterclockwise in FIG. 1). Thus the projection of pin 56 can be brought to bear against the underside of arm 62' of the latch lever 62 thereby disengaging the latch. Simultaneously the cam surface 49' is swung away from roller 51 SO that lever 44 can be urged in the counterclockwise sense by spring 65 to lift the plate 33 from the gimp. A new gimp thread G can then be introduced and the handle 59 released. The lever 44 is thus swung clockwise and brings the lever 62 into latching engagement to hold the clamp means closed.

After stitching of the buttonhole K, the latter is cut through as described in application Ser. No. 431,319.

The invention described and illustrated is believed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the appended claims.

I claim:

1. In an automatic buttonhole-stitching machine comprising support means, a fabric-carrying table longitudinally shiftable upon said support means, stitch-forming means on said support means co-operating with said table for stitching a buttonhole upon a fabric carried thereby, drive means connected with said table and said stitchforming means and actuatable for displacing said table from a starting position relative to said stitch-forming means into a stitching position wherein the sewing of a buttonhole is commenced and for operating said stitchforming means and said table to form the buttonhole and 10 for hereafter returning said table to said starting position, and an actuating element shiftably mounted on said support means and operatively connected with said drive means for actuating same following an initial movement of said element prior to energization of said drive means, the combination therewith of:

gimp-supply means for dispensing a gimp to be stitched into the buttonhole by said stitch-forming means;

means forming a path for said gimp from said supply means to said stitchiorming means;

gimp-preparation means along said path including said element and effective upon displacement of said element prior to actuation of said drive means for drawing a length of gimp from said supply means and disposing it loosely at said gimp-preparation means; and

gimp-clamping means on said table between said gimppreparation means and said stitch-forming means for clamping the free end of said gimp upon conclusion of a buttonhole-stitching operation and during operation of said gimp-preparation means but thereafter releasing said gimp for incorporation of the prepared length thereof in the buttonhole.

2. The combination defined in claim 1, further comprising gimp-severing means operatively connected with said drive means for cutting the gimp between the previously formed buttonhole and said clamping means upon movement of said table toward said clamping means retracting the free end of the gimp thus formed and subsequently positioning it at a stitching location of said table preparatorily upon advance of said table from said starting position to said stitching position.

3. The combination defined in claim 1 wherein said actuating element is an actuating lever swingably mounted on said support means and includes a shank rigid with said lever and directly engageable with the gimp, said gimp-preparation means further comprising a pair of eyes disposed on opposite sides of said shank and having said gimp threaded through them whereby displacement of said lever and said shank entrains the gimp between said eyes to form a loop of the gimp.

4. The combination defined in claim 1, further comprising co-operating control means on said table and said support means and operable in dependence upon displacement of said table for opening and closing said clamping means.

5. The combination defined in claim 4 wherein said control means includes latch means for releasably holding said clamping means in engagement with the gimp, and cam means co-operating with said latch means for releasing same to free the gimp for further movement.

6. The combination defined in claim 5, further comprising manual-release means operatively connected with said control means for disengaging said latch means and releasing the gimp to enable positioning of the gimp.

7. The combination defined in claim 5 wherein said clamping means include a rockable clamping plate car ried by said table and adapted to clamp the gimp thereagainst, said control means including a lever pivotally mounted upon said table and operatively connected with said plate for rocking same, said latch means being releasably engageable with said lever, further cam means engageable with said lever for displacing same into a latched position in which said plate retains said gimp, and adjusting means for relatively displacing the first-mentioned and said further cam means with respect to said table in the direction of displacement thereof.

8. The combination defined in claim 7 wherein said clamping means further comprises mounting means rockably connecting said plate with said table, said plate having an obtuse-angled bend and being provided with a plurality of upwardly diverging frustoconical recesses along the bend, said mounting means including respective generally spheroidal rings received in said recesses and screw means affixing said rings to said table.

9. The combination defined in claim 8 wherein said rings are split and radially expandable, said screw means comprising bolts with generally frustoconical heads for spreading said rings upon tightening of said screws.

10. The combination defined in claim 7 wherein said plate has a downwardly extending projection, said lever having a notch receiving said projection and an abutment, said latch means including a latch lever having a hook engageable with said abutment, said control means further comprising spring means bearing upon said levers for urging said hook toward said abutment, said levers each being provided with respective cam-follower rollers engageable with the respective cam means.

11. The combination defined in claim 7, further comprising a guide tube for said gimp forming said path between said clamping means and said gimp-preparation means.

12. The combination defined in claim 7, further comprising gimp-severing means operatively connected with References Cited by the Examiner UNITED STATES PATENTS 271,666 2/1883 Sullivan et a1. 112-253 X 757,463 4/1904 Hogan 112-253 X 1,330,555 2/1920 Searle 112-71 1,787,928 1/1931 Carlson 112-253 2,324,235 7/1943 Pikul 112-71 2,778,329 1/1957 Howell et a1. 112-199 FRANK J. COHEN, Primary Examiner. 

1. IN AN AUTOMATIC BUTTONHOLE-STITCHING MACHINE COMPRISING SUPPORT MEANS, A FABRIC-CARRYING TABLE LONGITUDINALLY SHIFTABLE UPON SAID SUPPORT MEANS, STITCH-FORMING MEANS ON SAID SUPPORT MEANS CO-OPERATING WITH SAID TABLE FOR STITCHING A BUTTONHOLE UPON A FABRIC CARRIED THEREBY, DRIVE MEANS CONNECTED WITH SAID TABLE AND SAID STITCHFORMING MEANS AND ACTUATABLE FOR DISPLACING SAID TABLE FROM A STARTING POSITION RELATIVE TO SAID STITCH-FORMING MEANS INTO A STITCHING POSITION WHEREIN THE SEWING OF A BUTTONHOLE IS COMMENCED AND FOR OPERATING SAID STITCHFORMING MEANS AND SAID TABLE TO FORM THE BUTTONHOLE AND FOR HEREAFTER RETURNING SAID TABLE TO SAID STARTING POSITION, AND AN ACTUATING ELEMENT SHIFTABLY MOUNTED ON SAID SUPPORT MEANS AND OPERATIVELY CONNECTED WITH SAID DRIVE MEANS FOR ACTUATING SAME FOLLOWING AN INITIAL MOVEMENT OF SAID ELEMENT PRIOR TO ENERGIZATION OF SAID DRIVE MEANS, THE COMBINATION THEREWITH OF: GIMP-SUPPLY MEANS FOR DISPENSING A GIMP TO BE STITCHED INTO THE BUTTONHOLE BY SAID STITCH-FORMING MEANS: MEANS FORMING A PATH FOR SAID GIMP FROM SAID SUPPLY MEANS TO SAID STITCH-FORMING MEANS; GIMP-PREPARATION MEANS ALONG SAID PATH INCLUDING SAID ELEMENT AND EFFECTIVE UPON DISPLACEMENT OF SAID ELEMENT PRIOR TO ACTUATION OF SAID DRIVE MEANS FOR DRAWING A LENGTH OF GIMP FROM SAID SUPPLY MEANS AND DISPOSING IT LOOSELY AT SAID GIMP-PREPARATION MEANS; AND GIMP-CLAMPING MEANS ON SAID TABLE BETWEEN SAID GIMPPREPARATION MEANS AND SAID STITCH-FORMING MEANS FOR CLAMPING THE FREE END OF SAID GIMP UPON CONCLUSION OF A BUTTONHOLE-STITCHING OPERATION AND DURING OPERATION OF SAID GIMP-PREPARATION MEANS BUT THEREAFTER RELEASING SAID GIMP FOR INCORPORATION OF THE PREPARED LENGTH THEREOF IN THE BUTTONHOLE. 